Create a landing page profile for the Citi GitHub organization

[JamieSlome]

The Citi GitHub organization landing page does not include introductory or getting started information. A hero is useful to quickly convey the purpose of Citi's open-source contribution efforts and if relevant, how to contribute.

Minimum Requirements ✅

• Create a /profile/README.md file
• Include links to our contribution guidelines & low-touch DCO sign-off process
• Create a hyperlink to our enterprise open source contribution guidelines
• Include a hyperlink to our opensource@citi.com e-mail address and purpose of address